Renal cell carcinoma metastasis presenting as an osteosarcoma

Abstract

A 72-year-old woman presented to our neurosurgery clinic with complaints of leg pain, weakness, and lumbar pain. There was no history of trauma, but there was a history of thyroid surgery. A lumbar lateral radiograph was performed, and the lumbar spine radiograph showed calcified lesions in the vertebrae posterior elements (Fig. 1). A spinal magnetic resonance imaging was performed and showed a lumbar extramedullary mass that was heterogeneous and hyperintense on T1-weighted and T2-weighted images (it was heterogeneously enhanced after contrast administration; Fig. 2). Magnetic resonance imaging showed involvement of the thoracolumbar vertebrae posterior elements, and the mass compressed the medulla spinalis and extended into the lumbar medullary canal (Fig. 3). According to radiological findings, the lesion was primarily osteosarcoma. However, when the mass was surgically removed, it was identified as a clear cell renal cell carcinoma via pathologic examination.